This application is based upon and claims the benefit of priority from the prior Japanese Patent Application PH 2001-022166, filed on Jan. 30, 2001; the entire contents of which are incorporated herein by reference.
The present invention relates to a route guidance generation apparatus and a method for generating route guidance for a pedestrian based on map information.
As a route guidance system of prior art, car navigation systems are widely used. Recently, by minituarization of GPS (Global Positioning System), a route guidance system using a portable terminal for a pedestrian is also used. In these systems, the present location of the pedestrian is measured using GPS or cellular phone, and a point and a route of the pedestrian are drawn on a map neighboring the pedestrian""s present location in order to execute the route guidance. Furthermore, an Internet service for route guidance for a cellular phone is used. In this case, the route guidance is presented by a sentence on a small-sized display of the cellular phone instead of the map.
In these route guidance systems, calculation of route is based on a method of Dijkstra well known as an algorithm to solve the shortest route. In this method, a route of minimum cost is calculated according to some evaluation standard. For example, the route of minimum cost of evaluation equation is calculated based on the evaluation standard in which a route length is short and a route width is wide (A wide road or a major street, for example). It is important that the route used for the guidance is short if possible and for the pedestrian not to lose his way. In the above-mentioned evaluation standard, xe2x80x9cthe route width is widexe2x80x9d represents a feature for the pedestrian not to lose his way.
However, even if a shape of junction point and a route width are complicated on the route, if the route includes sufficient landmarks, the pedestrian should not lose his way. Conversely, even if the route is simple, if a suitable landmark does not exist at a point of course change on the route such as an intersection, the pedestrian often loses his way. In short, in the route including necessary information for guidance at a point to be guided, it is initially important that the short route is calculated if possible. However, the route calculation in the prior system is insufficient for this aspect.
In a car navigation system including a portable terminal for the pedestrian, a predetermined base map is displayed in order along the route. In recent car navigation systems, navigation is often executed using speech synthesis. When a pedestrian reaches a junction point to change his way, these systems present the direction. Otherwise, the remaining distance to the next point to change his way is presented at a predetermined time or distance. This system is also insufficient from the aspect not to lose his way. The system is desirably controlled so that a detailed guidance is often presented at a point to be guided and a rough guidance is presented or not presented at a point not to be guided.
In another route guidance system, a method for displaying a simplified map or a guidance sentence is utilized. Especially, in a system automatically generating guidance, a size of the simplified map is changed based on type of a client""s terminal, or a text of the guidance is displayed for a terminal having a screen too small to display the map image. In this way, the route guidance is executed with a merit of automatic generation.
In case of generating a simplified map of small size, many landmarks cannot be drawn. In order for the pedestrian to understand, the route guidance had better be simple. From above-mentioned two aspects, it is necessary that information such as the route and the landmark appear in the guidance lessen if possible. From the original purpose of the route guidance, it is necessary for a suitable route guidance system to generate the route guidance satisfying minimum information not to get lost. However, the route guidance of the prior art is generated by uniform processing without evaluating which point is easy for the pedestrian to lose his way by what degree.
Ordinarily, it is important for the route guidance system to guide a route of the shortest distance without the pedestrian""s uneasiness to lose his way if possible. However, the route guidance system of the prior art makes much of the shortest distance route and makes light of the most important point not to get lost. Accordingly, the calculated route is not always the best route. Furthermore, in the generated guidance, the important aspect where a place easy to lose his way is, i.e., where a place to be sufficiently guided is, is not taken into consideration. Only a standardized guidance is generated.
It is an object of the present invention to provide a route guidance generation apparatus and method for effectively generating the route guidance along one route in order for the pedestrian not to lose his way.
According to an aspect of the present invention, there is provided a route guidance generation apparatus, comprising: an input unit configured to indicate a departure point and a destination point on map information; a calculation unit configured to extract a plurality of routes each connected from the departure point to the destination point from the map information, and to calculate a guidance demand degree of arbitrary points along each of the plurality of routes, the guidance demand degree being on evaluation value of the point based on a linearity of route, a complexity of route junction, and a change of route width; a route selection unit configured to select one route from the plurality of routes based on the guidance demand degree of each route; a guidance generation unit configured to generate guidance information of the point decided to guide based on the guidance demand degree along the one route; and a presentation unit configured to present the guidance information to a user.
Further in accordance with another aspect of the present invention, there is also provided a route guidance generation method, comprising: indicating a departure point and a destination point on map information; extracting a plurality of routes each connected from the departure point to the destination point from the map information; calculating a guidance demand degree of arbitrary points along each of the plurality of routes, the guidance demand degree being an evaluation value of the point based on a linearity of route, a complexity of route junction, and a change of route width; selecting one route from the plurality of routes based on the guidance demand degree of each route; generating guidance information of the point decided to guide based on the guidance demand degree along the one route; and presenting the guidance information to a user.
Further in accordance with another aspect of the present invention, there is also provided a computer program product, comprising: a computer readable program code embodied in said product for causing a computer to generate guidance information, said computer readable program code having: a first program code to indicate a departure point and a destination point on map information; a second program code to extract a plurality of routes each connected from the departure point to the destination point from the map information; a third program code to calculate guidance demand degree of arbitrary points along each of the plurality of routes, the guidance demand degree being an evaluation value of the point based on a linearity of route, a complexity of route junction, and a change of route width; a fourth program code to select one route from the plurality of routes based on the guidance demand degree of each route; a fifth program code to generate guidance information of the point decided to guide based on the guidance demand degree along the one route; and a sixth program code to present the guidance information to a user.
Further in accordance with another aspect of the present invention, there is also provided a server apparatus, comprising: a receiving unit configured to receive a route guidance request transmitted from a client terminal, the route guidance request including a departure point and a destination; a calculation unit configured to extract a plurality of routes each connected from the departure point to the destination point from map information, and to calculate a guidance demand degree of arbitrary points along each of the plurality of routes, the guidance demand degree being an evaluation value of the point based on a linearity of route, a complexity of route junction, and a change of route width; a route selection unit configured to select one route from the plurality of routes based on the guidance demand degree of each route; a guidance generation unit configured to generate guidance information of the point decided to guide based on the guidance demand degree along the one route; and a transmitting unit configured to transmit the guidance information to the client""s terminal.
Further in accordance with another aspect of the present invention, there is also provided an apparatus for supporting editing map information used for generation of guidance information to guide a route from a departure point to a destination point comprising: an extraction unit configured to extract at least one point of which a guidance demand degree is above a threshold as an investigation needed point from a plurality of points each having a guidance demand degree calculated based on a linearity of route, a complexity of route junction, and a change of route width on the map information, and to extract investigation contents of the investigation needed point by referring to the map information neighboring the investigation needed point; and an output unit configured to output a list including the investigation needed point and the investigation contents.
Further in accordance with another aspect of the present invention, there is also provided a method for supporting editing of map information used for generation of guidance information to guide a route from a departure point to a destination point, comprising; extracting at least one point of which a guidance demand degree is above a threshold as an investigation needed point from a plurality of points each having a guidance demand degree calculated based on a linearity of route, a complexity of route junction, and a change of route width on the map information: extracting investigation contents of the investigation needed point by referring to the map information neighboring the investigation needed point; and outputting a list including the investigation needed point and the investigation contents.
Further in accordance with another aspect of the present invention, there is also provided a computer program product, comprising: a computer readable program code embodied in said product for causing a computer to support editing of map information used for generation of guidance information to guide a route from a departure point to a destination point, said computer readable program code having: a first program code to extract at least one point of which a guidance demand degree is above a threshold as an investigation needed point from a plurality of points each having a guidance demand degree calculated based on a linearity of route, a complexity of route junction, and a change of route width on the map information; a second program code to extract investigation contents of the investigation needed point by referring to the map information neighboring the investigation needed point; and a third program code to output a list including the investigation needed point and the investigation contents.